Pen



FIG. 1 is a side elevational view of a pen showing our new design;

FIG. 2 is a side elevational view of the side opposite that shown in FIG. 1;

FIG. 3 is a front elevational view;

FIG. 4 is a rear elevational view;

FIG. 5 is a top plan view; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a pen, as shown and described. 